(cool nickname btw) to answer your first question, there is a method for this:

region = regions.getLabelRegion(i);

The second part is a bit more tricky. I’m afraid removing a region is not supported yet, but @tpietzsch may correct me here. I did something like that (the code is not open unfortunately) at some point where I collected all regions I wanted to keep in an ArrayList. After the list was filled, I went through a new image stack and filled all pixels with the corresponding index of the region in the list. This may be a bit slow but it does the thing. However, the LabelRegion API allows overlapping regions, while my approach does not.